The present invention relates to a fluid-treatment apparatus for treating with a fluid thin plate-like parts, such as semiconductor wafers, magnetic recording disk media, liquid crystal display panels and cathode ray tube shadow masks.
Conventional apparatus that wash plate-like parts such as silicon wafers in a fluid-treatment process include one disclosed in Japanese Patent Laid-Open No. 8-130202.
This cleaning apparatus has an upper cleaning plate (or upper fluid-treatment plate) opposing the top surface of a wafer, a lower cleaning plate (or lower fluid-treatment plate) opposing the bottom surface of the wafer, and a cylindrical wafer holder with its inner diameter equal to an outer diameter of the wafer. The wafer is held horizontally with the outer circumference of the wafer in contact with the inner circumference of the wafer holder. The upper cleaning plate and the lower cleaning plate are arranged parallel to the top and bottom surfaces of the wafer and spray a cleaning liquid onto the wafer""s top and bottom surfaces. As the wafer holder rotates, the wafer held by it is also rotated along with the wafer holder.
The cleaning liquid ejected from the center of the upper cleaning plate passes between the upper cleaning plate and the wafer top surface before being discharged from between the outer periphery of the upper cleaning plate and the outer periphery of the wafer top surface. A cleaning liquid ejected from the center of the lower cleaning plate passes-between the lower cleaning plate and the wafer bottom surface before being discharged from between the outer periphery of the lower cleaning plate and the outer periphery of the wafer bottom surface. The cleaning liquids flowing between the upper cleaning plate and the wafer top surface and between the lower cleaning plate and the wafer bottom surface generate pressures in respective spaces according to the Bernoulli theorem. When the wafer is washed, the pressure developed between the upper cleaning plate and the wafer top surface and the pressure developed between the lower cleaning plate and the wafer bottom surface are subtly balanced.
Though not described in the Japanese Patent Laid-Open No. 8-130202, this conventional technology is considered to have a cover enclosing the upper and lower cleaning plates and the entire wafer holder to prevent the cleaning liquid flowing out of the outer periphery of the wafer from being scattered around.
Such a conventional technology, however, has a drawback that because the wafer is held in the wafer holder only through a frictional force between the wafer and the inner circumferential surface of the wafer holder with which the wafer is in contact, if the balance between the two pressures, one generated between the upper cleaning plate and the wafer top surface and one generated between the lower cleaning plate and the wafer bottom surface, is lost even slightly, the wafer is shifted relatively easily from the wafer holder, causing a part of the rotating wafer to contact the cleaning plates, damaging or smearing the wafer.
Possible causes for breaking the pressure balance include, for example, a wafer being slightly tipped when it is mounted on the wafer holder. In such a case, the flow passage of the cleaning liquid may narrow at one part increasing the flow velocity and, at another part, widen reducing the flow velocity. The flow velocity difference will break the pressure balance. The pressure balance may also collapse when the amounts of cleaning liquid supplied from the upper and lower cleaning plates change. Once the pressure balance is lost, the wafer inclines further, which in turn aggravates the pressure imbalance, eventually resulting in a part of the wafer contacting the cleaning plate. Particularly when a gas is used as the working fluid, because the gas has a lower viscosity and a smaller specific gravity than a liquid, the wafer can very easily incline.
Further, in the conventional technology the cleaning liquid that has been thrown out of the outer periphery of the cleaning plates (hereinafter referred to as waste liquid) stays inside the cover as mist. When, after the wafer cleaning is finished, the cover and the upper cleaning plate are removed to take the wafer out, the waste liquid mist staying inside the cover adheres to the cleaned wafer, contaminating it.
It is therefore a first object of the present invention to provide a fluid-treatment apparatus that can firmly hold a rotating plate-like part to prevent its contact with other members thereby protecting it against being damaged or contaminated.
A second object of the present invention is to provide a fluid-treatment apparatus that can prevent a waste liquid from being scattered around and the plate-like part from being contaminated with the waste liquid.
A first fluid-treatment apparatus of the present invention to achieve the first object described above is characterized by: a plurality of chuck members each having a chuck groove into which an outer periphery of the plate-like part fits, the chuck members being spun on their own axes to assume two states, one of the two states being a chuck state in which the outer periphery of the plate-like part fits in the chuck grooves of the chuck members, the other being a chuck wait state in which the outer periphery of the plate-like part is disengaged from the chuck grooves; a chuck member spin mechanism to spin the plurality of chuck members on their own axes to bring all the chuck members as one piece into the chuck state and the chuck wait state; and a chuck member revolution mechanism to revolve the plurality of chuck members as one piece about an axis to spin the plate-like part chucked by the plurality of chuck members on its own axis.
A second fluid-treatment apparatus to achieve the first object is characterized by the first fluid-treatment apparatus which further includes a chuck member moving mechanism to move the plurality of chuck members in a direction parallel to a revolving axis of the plurality of chuck members.
A third fluid-treatment-apparatus to achieve the first object is characterized by the first fluid-treatment apparatus which further includes: an inner wheel formed cylindrical and having as its center the revolution axis of the plurality of chuck members; an outer wheel formed cylindrical and having as its center the revolution axis, the outer wheel having an inner diameter larger than an outer diameter of the inner wheel; a relative rotation means to rotate the inner wheel relative to the outer wheel about the revolution axis; and an integral rotation means to rotate the outer wheel and the inner wheel together about the revolution axis; wherein the plurality of chuck members engage the outer wheel and the inner wheel so that they spin on their own axes by the relative rotation between the outer wheel and the inner wheel and revolve about a center by the integral rotation of the outer wheel and the inner wheel; wherein the chuck member spin mechanism comprises the inner wheel, the outer wheel and the relative rotation means; wherein the chuck member revolution mechanism comprises the inner wheel, the outer wheel and the integral rotation means.
A fourth fluid-treatment apparatus to achieve the first object is characterized by the third fluid-treatment apparatus, wherein one of the inner wheel and the outer wheel is disposed to be movable in a direction parallel to the revolution axis, the plurality of chuck members engage the one of the wheels so that they cannot move relative to the one wheel in a direction parallel to the revolution axis, and a chuck member moving mechanism is provided to move the one wheel in a direction parallel to the revolution axis.
A fifth fluid-treatment apparatus to achieve the first object is characterized by the third fluid-treatment apparatus, wherein one of the inner wheel and the outer wheel is formed in its circumferential surface with a cam groove, the cam groove extending progressively toward a direction parallel to the revolution axis as it advances around the revolution axis, and the chuck members are each formed with a cam follower portion that fits into the cam groove;
wherein the chuck members are mounted to the other of the inner wheel and the outer wheel so that the chuck members rotate together with the other wheel.
The sixth fluid-treatment apparatus to achieve the first object is characterized by the third or fourth fluid-treatment apparatus, wherein the chuck members have a gear formed on each of their surfaces around their spin axes; wherein the outer wheel has formed in its inner circumferential surface arc grooves each of which can accommodate a part of the gear of each of the chuck members; wherein the inner wheel has formed in its outer circumferential surface around its revolution axis a gear engageable with the gear of the chick members.
A seventh fluid-treatment apparatus to achieve the first object is characterized by the third or fourth fluid-treatment apparatus, wherein a cam pin is secured to the circumferential surface of one of the inner wheel and the outer wheel; wherein the chuck members each have a cam follower portion, the cam follower portion having a groove into which the cam pin can fit and rotation restriction surfaces on both sides of the groove which are formed in a reversed shape of the circumferential surface of the one wheel; wherein the chuck members are mounted to the other of the inner wheel and the outer wheel so that they can be rotated together with the other wheel and can also spin on their own axes.
An eighth fluid-treatment apparatus to achieve the first object is characterized by any one of the third to seventh fluid-treatment apparatus, which further includes: a fluid-treatment plate moving mechanism to move the fluid-treatment plate in a direction parallel to the revolution axis of the plurality of the-chuck members.
A first fluid-treatment apparatus of the present invention to achieve the second object described above is characterized by a fluid-treatment apparatus, in which a fluid-treatment plate faces parallelly at least one of two almost parallel surfaces of a plate-like part and a treatment fluid is ejected from the fluid-treatment plate onto the one surface of the plate-like part while rotating the plate-like part to fluid-treat the plate-like part, and which comprises: an enclosure member enclosing the outer periphery of the plate-like part and the outer periphery of the fluid-treatment plate to receive the treatment fluid injected between the plate-like part and the fluid-treatment plate and discharged from between the outer periphery of the plate-like part and the outer periphery of the fluid-treatment plate; a treatment fluid recovery line to introduce the treatment fluid remaining in the enclosure member to a target location; a gas-liquid separator having a liquid outlet, a gas outlet and a waste liquid inlet, the waste liquid inlet being connected to the treatment fluid recovery line; and a suction means connected to the gas outlet of the gas-liquid separator to evacuate by suction the interiors of the gas-liquid separator, the treatment fluid recovery line and the enclosure member.
A second fluid-treatment apparatus to achieve the second object is characterized by the first fluid-treatment apparatus for realizing the second object wherein the treatment fluid recovery line includes a cylindrical conduit with a rotating axis of the plate-like part as its center and a recovery pipe connected to the cylindrical conduit; wherein the enclosure member has a cross section taken along a plane perpendicular to the rotating axis which is circular about the rotating axis as its center, and the enclosure member rotates about the rotating axis as the plate-like part rotates; wherein the cylindrical conduit has its one end surface formed as a sliding contact surface in sliding contact with the rotating enclosure member and also has a groove extending from the one end surface toward the other end surface; wherein the recovery pipe has its one end connected to the groove of the cylindrical conduit and the other end connected to the waste liquid inlet of the gas-liquid separator.